Manufacture of viscose.



UNITED STATES PA E T, ornilon.

- MONTGOMIERY'WADDELL, OF NEW .YORK, N. Y.', ASSIGNOR, BYIMESNIL AS- SIGNMENTS, TO suns W. PETTIT, or PHILADELPHIA, PENNSYLVANIA.

"MANUFACTURE OF viscose mfs'saais.

Specification of Letters Patent; Application filed July 7,1904. smuraziaevo.

Patented May as, 1907.

to Letters Patent of the United States No.

622,087, dated March 28th, 1889, and No. 716,778, dated Dec. 23rd, 1902, ascontaining de'scri tions of typical and convenient methods o obtainin such filaments.

To form suc h filaments, the viscose is forced through spinnerets into a bath capable of gelatinizing the viscose, whereby the filaments thus produced are set in the form given to them by the s'pinnerets.

It is to be understood that a viscose absolutely free from any traces of undissolved fibers is highly desirable in the manufacture of such filaments, for, of course, any such fiber particles in theviscose tend to block the small 0 enings of the spinnerets, thereby break the filaments and prevent their formation in continuous len ths.

It is the princi al 0 ject of my invention to produce a col ulose which is ofuniform character and consistency and free from any undissolved fiber particles.

A. further object of my invention is to control the noxious vapors liberated during the process of manufacture and prevent their escape into the atmosphere.

The ordinary method of roducing viscose, for the manufacture of ms, filaments and other well known products, is to immerse pulp, in sheet form, inan excess of sodium 1y rate for twenty-four hours. Thereafter, the excess of sodium hydrate is removed by pressure and the alkali cellulose is allowed to stand for forty-eight hours a ing in order that the remaining sodiumhy rate may diffuse uniformly throughout the mass. The alkali cellulose is then subjected, in a closed rotating vessel,- to the action of about twenty per cent of its weight of carbon bisulfid, which converts the cellulose into cellulose xanthate and incidentally vaporizes. There is always a residue of carbonbisulfid vapors which cannot be condensed on account of their admixture with air, and, it has been the practice to permit said vapors to escape into the atmosphere regardless of the fact that they are prejudicial to health.

I have found that during the time when the alkali celluloseis beingtreated as above described, it is particularly susce tible to the action of air, by which-thefirst ormed portions of cellulose xanthate are likely to be partially'or wholl reverted while the remainder of. the co into xanthate.

My invent ion isintended to avoid the objectionable features aforesaid, and to that end I roceed as follows :I submerge alkali ce ulose in carbon bisulfid, in a vessel which is 1 maintained hermetically sealed until the treatment is completed. I then ulose is being converted drain on as. much as possible of the carbon bisulfid and cover the remaining cellulose xanthate with an aqueous solution of sodium hydrate, of the strength and propoltion' required to render said xanthate of the re- Snred consistency for forming filaments.

urin the treatment of the mass with sodium hydrate, the excess of carbon bisulfid, remaining from the draining operation aforesaid, is removed by means capable of forming a partial vacuum within the closed vessel. The vapors thus liberated and removed from the mass within said vessel, being entirely free from air, can be readily condensed and prevented from issuing into the atmosphere.

During the treatment of the mass with.

sodium hydrate asabove described, I find it advantageous to a itate the same and this ma be convenient y effected by rotary agi-- tatlon.

My invention is advantageous in that 'viscose produced in accordance therewith is more uniform than viscose rodu'ced in accordance with the aforesai process of the prior art, because it is at all tlmes immersed in a liquid which excludes the cellulose from contact with air, and, as above noted, the present process permits complete control of the noxious vapors liberated from the mass under treatment.

I have also found that, when alkali cellulose is treated by the old method above described, the first formed xanthate tends to form into large dense massespreventing the complete treatmentof the interior until'aftor the exterior is overtr'eated; whereas,- in my process, the alkali, cellulose is entirely surrounded by the liquid, which pr'eventssuch agglomeration,

the xanthate so formed is more readily dissolved in the sodium hydrate necessary torender it of the required carbon bisulfid from the mass; then covering the xanthate with an aqueous solution of a solvent; and removing the surplus carbon bisulfid as vapor, substantially as set forth.

consists in submergi -2. The hereinbefore described improvement in the manufacture of viscose, which less in carbon bisulfi until it is converted into cellulose xanthate while secluding the same from the atmosphere; draining the free carbon bisulfid from the mass; then covering the xanthate wit an aqueous solution of a solvent; and. re' oving the "surplus carbon bisulfid as. vapor, by reducing a partial vacuum adjacent to sai mass, substantially as set-forth.

3. The hereinbefore described improvesodium hydrate; agitating the mass during said treatment; and, removing the surplus I a mass of alkali cellu ment in the-mannfacture of viscose, consists in submergm a mass of alkali cellu-" .lose in carbon blsulfi until it is-converted'* 5 into cellulose xanthatewhile secluding the same from the atmosphere; draining the free carbon bisulfid from the mass; then covering the 'xanthate with an aqueous solution 0 carbon bisulfid as vapor, by roducing a par-' tial vacuum adjacent to said mass, substan- 'tially as set forth.

4. The herein described im rovement in bon bisulfid, until it is converted into cellulose xanthate while secludin the same from the atmosphere, draining t e free carbon bisulfid from the mass, then covering the xanthate 'with an aqueous solution of a solvent until of the required consistency for forming filaments, and then removing thesurplus carbon bisulfid, substantially as set forth. I

In. testimony whereof, I have hereunto sifgned my name, at Lansdowne in the State Pennsylvania this twenty-eighth day of, June 190 MONTGOMERY WADDELL. Witnesses:

WILLIAM H. KETTRA,

. Jos. A. O DoivNnLL.

45 the manufacture of viscose WlllCh consists 1n sub'merging a .mass of alkali cellulose in car- 

